1. Field of the Invention
The present invention relates to a process for the production of granular sodium perborate monohydrate having good mechanical strength.
2. Description of the Prior Art
Granular sodium perborate monohydrate NaBO.sub.2.H.sub.2 O.sub.2 is obtained by dehydrating the corresponding granular tetrahydrate NaBO.sub.2.H.sub.2 O.sub.2.3H.sub.2 O.
Relative to the tetrahydrate, perborate monohydrate shows essentially three advantages: a higher titer in active oxyen, a higher heat stability and a greater solution rate.
It is however known that perborate monohydrate is considerably brittler than the tetrahydrate, and this is one of the main reasons which so far have limited its use.
Such a drawback is in fact particularly detrimental, because it leads, during the handling of the product, to a change of its granulometric distribution, with an increase in finer fractions. The fine product creates dust during its use, and hence causes problems of environmental hygiene.
Furthermore, while perborate tetrahydrate is usually moved in bulk, this cannot be realized with perborate monohydrate which would be easily crushed by the pneumatic conveying plants, utilized, at present, everywhere.
For the reason above stated, monohydrate is moved only in bags, with higher packaging costs and reduced storing capacity.